A Study On The Role Of Autophagy In Vitro Maturation Of Mouse Oocytes

Oocytes make provision for fertilization and subsequent embryonic development by genome modification and accumulating the necessary maternal factors in the process of mature.oocyte requires a lot of energy and nutrients such as amino acids,glucose,nucleotide in the process.however,the system is not perfect for in vitro maturation of oocytes,there are some substances that are vital to mature and subsequent embryonic development is insufficient,thus affecting the quality of oocyte maturation.A variety of adverse stimuli similar to the oxidative stress,hunger,or lack of cumulus cell apoptosis,make some damaged organelles of oocytes,And produce many harmful cell component.So it is difficult to obtain high quality oocytes in the process of in vitro maturation.Autophagy is a process of reuse that degradation of damaged organelles and macromolecule material through the lysosome.Studies have shown that autophagy for mammalian early embryonic development is very important.While a critical role of autophagy in mammalian early embryogenesis has been demonstrated,few studies have been conducted regarding the role of autophagy in in vitro maturation of immature oocytes.So we study the change rule of autophagy in the process of in vitro maturation of oocytes,as exemplified by mice.We study the role of autophagy in vitro maturation of oocytes under different culture conditions.The results were as follows:1.We found that by testing autophagosome in oocyte matured in diffirent time,autophagy is always exist in the mature process of mouse oocytes,and the expression level shows its descending following its ascending of autophagy in the mature process of mouse oocytes.2.By testing autophagosome in oocyte matured in different conditions,we find autophagy expression level is higher in the worse mature conditions of oocytes.3.We found that autophagy affect more significantly the oocyte matured in worse mature conditions when we induce or inhibit the autophagy of oocyte under the different mature condition,4.After inducing or inhibiting autophagy,we found that Autophagy can improve the quality of oocyte by resisting oxidative stress in oocytes by testing the level of ROS and GSH in oocyte.5.After inducing or inhibiting autophagy,we found that autophagy can improve the quality of oocyte by inhibiting the apoptosis of cumulus cells.by testing apoptosis-relating genes BCL-2 and BAX.In conclude,Autophagy is always exist in the mature process of mouse oocytes.And autophagy plays an important role in oocyte maturation under the condition of nutrient deprivation.